To cancel your ChatGPT subscription, be sure to do it through the same platform...

https://wiki-zine.win/index.php/What_if_the_Stripe_Billing_Portal_Never_Opens_for_ChatGPT%3F

To cancel your ChatGPT subscription, be sure to do it through the same platform where you subscribed—whether that’s the web, Stripe, Apple, Google Play, Business, or API